#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,n)for (int i = 0; i < int(n); ++i)
#define rrep(i,n)for (int i = int(n)-1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template<class T> void chmax(T& a, const T& b) {a = max(a, b);}
template<class T> void chmin(T& a, const T& b) {a = min(a, b);}
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

int dp[3010][3010];

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    VI a(n);
    rep(i, n) cin >> a[i];
    sort(rall(a));
    rep(i, n) {
        int d = (i + 1 < n ? a[i] - a[i + 1] : -1);
        int v = a[i];
        rep(j, m + 1) {
            chmax(dp[i + 1][j], dp[i][j]);
            if (i + 2 <= n && j + d <= m) {
                chmax(dp[i + 2][j + d], dp[i][j] + v);
            }
        }
    }
    int ans = 0;
    rep(j, m + 1) chmax(ans, dp[n][j]);
    cout << ans << '\n';
}